Device to audibly express impendance measurement

ABSTRACT

An Audio Feedback Impedance Comparison Device to audibly express Impedance differences between/amongst components, circuits, materials, substances etc., to make use of the aural sense, while relieving eye, neck and mental strain, as well as reduce probe time. This is achieved by allowing simultaneous yet focused attention to be paid to all aspects of an impedance probe, i.e. hand-eye coordination of probe positioning, while aurally monitoring the feedback, instead of the common practices/methods where eyes have to be re-focused on visual feedback devices. The use of an alternating signal allows “through” comparison, where multiple components some of which are impervious to static signal, contribute to overall impedance. The device can be used to inject and/or detect/trace the presence of an audio signal in an active circuit. With the aid of transducers, this Device may be used with other forms of energy.

BACKGROUND OF THE INVENTION

This Invention is as a result of a quest to find a cheap, simple andeffective way to troubleshoot malfunctions due to Impedance change,since component failure is usually reflected as such.

DESCRIPTION OF PRIOR ART

In Electronics, the current method of troubleshooting is generally toverify that individual components within a circuit retain their ratedmanufactured properties. The various properties usually requiredifferent methods and sometimes full or partial removal/isolation, toobtain accurate measurements. The Test Equipment most commonly used toverify component properties is the multi-meter, and since mostmulti-meters operate with a D.C. test Signal, they are unable to checkReactive Impedances. The main feedback from Multi-meters is visual,therefore using a Multi-meter requires firstly, visual attention in thepositioning of the probes, then, refocusing on a display to read avalue. Comparison between two circuits requires either two multi-meters,or checking and recording each reading. Testing is sometimes also doneusing a signal generator and oscilloscope. This method, though veryeffective, requires two pieces of equipment, still uses visual feed backand is relatively expensive. These current methods are not primarilygeared for comparison. Comparisons are usually done as a choice ofmethod by the investigator.

Some prior art systems include U.S. Pat. No. 5,272,445 to Lloyd et al.in which is disclosed a portable resistance tester comprised of a pairof DC regulator circuits used to drive a bridge circuit and a detectorcircuit, when measuring the resistance of “in-circuit” test nodes. Thetester uses the passage of Direct Current to determine when theresistance of a measured test node falls within or without apredetermined resistance range. This said invention therefore, relatesto testing of resistance and more specifically, to a tester formeasuring/referencing resistance values only, with a binary output, asdistinct and apart from the functions of the present invention whichmeasures impedance in its totality, within or without of any givencircuit.

German Patent No: DE 4,340,831 to Taco-Tafel GMBH, yet another inventionemploying a bridge circuit and a DC signal, relates to measurement,either of component resistance or of resistance formed at contact pointsin networks, with audio/visual indicators, where the audio indicator, isa tone whose frequency varies inversely with the resistance beingtested. Again as aforementioned, the test signal is DC, which is capableonly of measuring resistance.

Final reference is made to U.S. Pat. No. 4,004,223, to Cohen relating toa resistance or voltage tester for producing an audible tone that variesinversely with resistance or voltage. The device comprises an audiblewide range resistance and medium range voltage tester in the form of arectangular small box designed to fit into a shirt pocket. The testerincludes a speaker driven by low current logic gates and a transistor.The frequency of the speaker varies inversely proportional to themeasured resistances ranging from zero to over 50 Meg Ohms and alsoinversely proportional to the voltage measured. In particular cases, thedevice can also be used as an audio signal source and with the use of asuitable probe, the voltage range can be increased to +400V DC or 260VAC. Again, the impedance test signal is DC which limits the test toresistance only.

In summary therefore, demonstrably, as can be seen clearly in the priorart, none of them employ AC as their test signal and thereforeexplicitly do not address the fundamental operational principle ofcontemporary impedance measurement testing of electrical or electronicdevices or systems, since in their given previous and current modusoperandi, AC is employed for use only as a mere indicator. It is evenfurther more abundantly clear, that by employing DC as their testsignal, none of the existent prior art devices, have to date evenremotely addressed the concept of a systemic electronic device, whichprovides for impedance measurement. By employment of AC as its testsignal and an external reference, this preferred electronic systemicdevice of the present invention, measures all aspects of impedanceincluding resistance and indicates the measure of impedance via sound.

SUMMARY OF THE INVENTION

The Invention uses analog components in this digital era, to quicklyisolate faults even in these modern digitized pieces of equipment.

DESCRIPTION OF THE INVENTION

The Operation of the Dynamic Impedance Comparator is explained using thefollowing thirteen (13) diagrams.

FIG. 1. An Audio Frequency Voltage Generator called ‘AC’, whose Outputis applied to the points labeled ‘In’, in Figure two (2) through Figuresix (6).

FIG. 2. (The Fundamental Circuit). A Resistive Bridge where ‘R1’ equals‘R2’, and ‘RA’ and ‘RB’ are of unknown value. ‘R1’ and ‘R2’ also act ascurrent limiters in the Circuit. Any difference in the Resistances of‘RA’ and ‘RB’, causes a Voltage to be present across the points labeled‘Out’. The Circuit can be said to consist of two halves. One consistingof ‘RA’ and ‘R1’, and the other consisting of ‘RB’ and ‘R2’.

NB. If any Measuring Device were to be connected across the terminalslabeled ‘Out’, the power drawn by this Device, would change the Voltageacross these terminals, hence the following configuration.

FIG. 3. Operational Anplifiers (Op-Amps) ‘A1’ and ‘A2’, and Resistors‘R3’ and ‘R4’ with resistances equal to ‘R1’ and ‘R2’, are now added toFIG. 2. The Op-Amps are configured as Unity-Gain Inverting Amplifiers,with the positive (+) inputs grounded, and ‘R1’ and ‘R2’ used as theInputs. The physically grounded points of ‘R1’ and ‘R2’ in FIG. 2., arenow virtually grounded at the union of the Negative (−) Input of ‘A1’and ‘R3’, and the union of the Negative (−) Input of ‘A2’ and ‘R4’respectively. The Output at the terminals labeled ‘Out2’ between theunion of ‘R4’ and the Output of Op-Amp ‘A2’, and the union of ‘R3’ andthe output of Op-Amp ‘A1’, is equal in phase and magnitude to output atthe terminals labeled ‘Out2’ between the union of ‘RA’ and ‘R1’, and theunion of ‘RB’ and ‘R2’ respectively.

FIG. 4. The Outputs of the Op-Amps labeled ‘Out2’ in FIG. 3. is nowconnected to a Sound Reproduction Device labeled ‘Speaker’. AnyDifference in the Resistance between ‘R1’ and ‘R2’ can now be “heard”.

FIG. 5. When Resistances ‘RA’ and ‘RB’ in FIG. 3. are replaced withImpedances ‘ZA’ and ‘ZB’, which may comprise of Resistive, Capacitive,Inductive or Semi-Conductive properties of Electronic or ElectricalCircuits or Components, or reflections of the electrical properties suchas resistance dielectricity, magnetic permeability of substances ormaterials, Impedance Differences are made audible.

FIG. 6. The addition of equal resistances ‘R5’ and ‘R6’ to FIG. 5.,allows for increased currents through the Impedances ‘ZA’ and ‘ZB’respectively, without increasing the currents through the Op-Amps, yetstill producing a voltage across the speaker, equal to that across the‘separate’ terminals of ‘ZA’ and ‘ZB’.

FIG. 7. The Unknown Impedances ‘ZA’ and ‘ZB’ in FIG. 6. have now beenseparated from the rest of the circuit. The Point of union (labeled ‘In’in FIG. 6) of the Unknown Impedances, and the free ends of the UnknownImpedances provide three (3) terminals. FIG. 1. is now integrated intothe rest of the circuit eliminating the need for Ground, which was beingused as a reference to unite FIG. 1., to FIG. 2. through FIG. 6. ‘R5’and ‘R6’ have been made selectable by adding Ganged Switch ‘SA’, ‘SB’.The connector labeled ‘C’ (Common), previously called ‘AC’, togetherwith connectors labeled ‘A’ and ‘B’ at the free ends of ‘R1’ and ‘R2’respectively also provide three (3) terminals. These are the Terminalsof this (Basic Version) Test Device called the Dynamic ImpedanceComparator. NB. The ratio of the values of the Resistors ‘R1’ to ‘R4’,though introduced as equal, along with the Values of ‘R5 and R6’, can bevaried or even replaced with complex Impedances or an Impedance networkto

-   -   1. accommodate proportional impedances, or    -   2. vary the gain of the amplifiers to increase or decrease        sensitivity.        The Op-Amps may also be replaced with High Voltage/Power        Frequency Amplifiers ‘Amps’, functioning in the same manner, and        retaining the labels ‘A1’ and ‘A2’, for Industrial Applications.        The ‘Speaker’ may also be isolated from the Circuit as        necessary. This concept is only demonstrated using electricity        and electrical impedance. However, impedances to other forms of        energy e.g. sound, motion, light etc., can be monitored and        compared by energy conversions/adaptations some of which are        stated below. When the Energy produced by ‘AC’ is in the form of        sound, motion, light etc., appropriate transducers may be used        to convert the energy flow, or reaction to this energy, to        Sound.

FIGS. 8 through 13 illustrate modifications to accommodate variousUnknown Impedance and/or Configurations.

FIG. 8. Connector ‘C’ is split to two terminals, to provide forcomparison of Separate Impedances.

FIG. 9. Resistors ‘R1’ through ‘R6’ have been replaced with Impedances‘Z1’ through ‘Z6’ to enhance specific characteristic differences ofCompound Impedances.

FIG. 10. Impedances ‘Z1’, ‘Z2’, ‘Z5’ and ‘Z6’ have been removed from theCircuit in FIG. 9 and the Unknown Impedances are connected directly to avariation of the Dynamic Impedance Comparator. This configuration makesthe Unknown Impedances the sole Current (inversely proportional to theImpedance) determining factors in each half of the circuit, which inturn, is responsible for the Voltage across the Speaker.

FIG. 11. NB. Impedances ‘Z3’ and ‘Z4’ are removed for simplicity. Inthis configuration, Impedances ‘Z1’ and ‘Z2’ form the Inputs to theInverting Amplifiers. This configuration regulates the Currents to theImpedances ‘ZA’ and ‘ZB’ in another variation of the Dynamic ImpedanceComparator. If ‘Z1’ and ‘Z2’ then the Currents will be equal causing theVoltage (directly related to current) across the Speaker, to be basedsolely on the Impedance difference between ‘ZA’ and ‘ZB’.

FIG. 12. Due to the numerous possible configurations, the Circuit isrepresented as an Impedance Network where the Unknown Impedances, areattached as components of the Network.

FIG. 13. For checks on Single Impedances, comparison may be made withSimulated or Pre-Recorded Signals.

SUMMARY OF MODIFICATIONS

Input Modifications include transducers to detect non electricalproperties such as motion, light, sound, pressure.

AC Modifications include higher or lower power with variable, sweep,pulsed, intermittent, customised, higher than audible frequencies etc.Pre-Recorded ‘AC’ and Output Signal to be used as a reference forstand-alone checking.

Circuit Modifications higher or lower power/frequency handlingamplifiers with customised Impedances.

Output Modifications include the replacement of the Speaker withamplifiers, attenuators, transducers, isolators, recorders, metersrectifiers, oscilloscopes, computers.

Configuration An inverting amplifier was only used to demonstrate thecircuit, however, non-inverting or other configurations may also beused.

1. A testing system for measuring impedance, comprising: a) an AC signalfor excitation of a subject impedance; and b) an adaptable referencecomprising: i) a reference impedance, ii) a reference signal, whereinthe reference signal comprises at least one of (1) a playback of apre-recorded and signal and (2) a simulated signal, wherein the ACsignal, the adaptable reference and the subject impedance are configuredin a circuit to generate an output signal as a measure of the subjectimpedance, and wherein the output signal is proportional to an imbalancebetween the subject impedance and the reference impedance and/orreference signal.
 2. The testing system of claim 1, wherein the outputsignal is expressed as an audible sound signal.
 3. The testing system ofclaim 1, wherein the subject impedance is an activeelectrical/electronic system or sub-system, and wherein the testingsystem expresses a measure of a processing deviation of the AC signal inthe active electrical/electronic system or sub-system via injection andtracing of the AC signal with respect to the adaptable reference.
 4. Atesting system for measuring a property of a subject element, whereinthe property is a property selected from the group of electrical,electronic, impedance, transparency, reflectivity, structural,soundness, mass, shape and any combination thereof, the testing systemcomprising: a) an AC signal for excitation of a subject element; and b)an adaptable reference comprising: i) a reference element, ii) areference signal, wherein the reference signal comprises at least one of(1) a playback of a pre-recorded signal, and (2) a simulated signal,wherein the AC signal, the adaptable reference and the subject elementare configured in a circuit to generate an output signal as a measure ofthe property of subject element, and wherein the output signal isproportional to an imbalance between the subject element and thereference element and/or reference signal, wherein the testing systemfurther comprises a transducer that is excited by the AC signal, andwherein the transducer is responsive to a form of energy selected fromthe group of electricity, light, sound, vibration, motion and anycombination thereof.
 5. The system of claim 4, wherein the testingsystem is configured for the measurement of structural integrity withrespect to the adaptable reference, and wherein the system expresses themeasure of the property as vibrational energy via the transducer.
 6. Thesystem of claim 4, wherein the testing system converts the AC signal toan energy form corresponding the transducer, wherein the subject elementis an active electrical/electronic system or sub-system, and wherein thetesting system expresses a measure of a processing deviation of the ACsignal in the active electrical/electronic system or sub-system withrespect to the adaptable reference, via injection and tracing of the ACsignal in the converted energy form.
 7. The testing system of claim 4,wherein the AC signal, the adaptable reference and the subject elementare configured as a bridge circuit.